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head steady stud threads in head

Discussion in 'Other Norton Motorcycles' started by seattle##gs, Nov 25, 2018.

  1. seattle##gs

    seattle##gs

    Joined:
    Oct 28, 2014
    the head steady stud is 3/8 what? in the head. I know it is british. If the threads cannot be saved what is the best way to make new threads? There is not much aluminum to work with. Is there enough room to accept a helicoil for american?
     
  2. norton bob

    norton bob

    Joined:
    Nov 29, 2013
    Should be a course thread in alloy, whitworth or similar ,if you are getting a new stud ?, had mine welded and just re-tapped as was. All done with hand tools by eye as not critical .
     
  3. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
  4. seattle##gs

    seattle##gs

    Joined:
    Oct 28, 2014
    I do not have the stud yet. It is a fine thread in the head so it must be 26TPI. The old owner tried to jam an american bolt in the hole but fortunately gave up before destroying all of them. With luck I cans send a brit tap down the hole and still use it.
     
  5. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    As the stud is supposedly 20-26 then it's more likely to be BSF.


    https://andover-norton.co.uk/en/shop-drawing/491/head-steady
    The upper end of the stud (9) must be the 26 tpi end so the 'coarser' end is almost certainly 20 BSF.

    Commando head steady threads are (5/16) BSF.
     
  6. seattle##gs

    seattle##gs

    Joined:
    Oct 28, 2014
    OK...I'll need a tap for it.
     
  7. dynodave

    dynodave

    Joined:
    May 28, 2003
    pre commando aluminum head studs are 3/8-20 bsf
    only early iron heads are 3/8-26cei/cycle
     
  8. seattle##gs

    seattle##gs

    Joined:
    Oct 28, 2014
    If I have to helicoil what is the best size? SAE? is the enough aluminum for a helicoil?
     
  9. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    If you are a purest, and want to replicate what was originally there, assuming you have a pre-commando since you posted in this Forum, you will need part No. 18032 stud, E3224 Nut, and 000010 washer. Then you will have to tap or helicoil the head to fit the stud (3/8 - whatever it is). I do not have a head to view, but I would expect there is plenty of material to insert a helicoil, no matter if it is BSF, or UNC.

    Slick
     
  10. seattle##gs

    seattle##gs

    Joined:
    Oct 28, 2014
    It is an Atlas circa 1964, the head steady hole as usual is damaged. I would like to install a 3/8 stud either course or fine with a helicoil. Not sure what thread would be optimum. I know the three head studs...#7...#8...#2...had the wrong thread type,would like to avoid that problem
     
  11. Deets55

    Deets55 VIP MEMBER

    Joined:
    Oct 3, 2013
    Generally speaking all the studs I have seen in aluminum have the coarse thread in the aluminum and the fine thread exposed for the nut.
    Pete
     
  12. Dutch

    Dutch

    Joined:
    Sep 21, 2015
    Where a course thread has more thread depth, being located stationary in the head makes sense.
    A fine thread gives more torque while being tightened down, what you would want pulling against that stud.
     
  13. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    Part number 18032 stud for the Atlas is not the usual "stud", there being a hex section between the coarse and fine threads. One tightens it into the head using a ring or open end spanner.

    If you wish to retain that originality, your course is set ..... The long end with the coarse thread goes into the head. You will need the proper 3/8 British thread helicoil and tap drill ..... probably not easy to find.

    If you wish to make your own stud, I would helicoil for a 3/8-16 NC. As Deets55 says, the coarse thread is in the aluminum, the fine thread (3/8-24) for the grip end. If you go this route, you will need a stack of washers, or a ring spacer, to make up for the missing hex section, otherwise the head steady brace will not properly align on the head.

    Slick

    Edit: The thickness of the hex section is about 3/8 inch, as best I can "eyeball" it without removing the brace.
     
    Last edited: Dec 5, 2018